Adsorption Behavour Of Contaminants In Wastewater By Tannin-sewage Sludge

In this paper, tannin-sewage sludge(TASS) was prepared by sewage sludge(SS) frommunicipal wastewater treatment and tannin. Then SS and TASS were used to removal ofCr(Ⅵ)-containing wastewater, tartrazine-containing wastewater and soy sauce wastewater asadsorbent. Adsorption behavior was investigated by experiment, and the removal mechanismwas studied by Scanning Electron Microscope(SEM), X-ray diffraction(XRD), Fouriertransform infrared spectra(FTIR). The results of this study were summarized as follows:（1） TASS and TSAG were both effective for adsorption of Cr(Ⅵ). The removalefficiency of Cr(Ⅵ)(＜102mg·L-1) were both up to100%by TASS and TSAG. The result ofcolumn experiment revealed that the concentration of Cr(Ⅵ) in effluent could be reduced to0.5mg·L-1by TSAG. The adsorption process onto TASS and TSAG follows well to thepseudo second order kinetic model and Langmuir isotherm model. The removal of Cr(Ⅵ)was mainly occurred on the surface of TASS and TSAG. Esterification reaction andcomplexation between tannin and Cr(Ⅵ)/Cr(Ⅲ) were found during the adsorption process.（2） Both SS and SSAG were effective to remval of tartrazine. Under the optimumconditions, the removal efficiency of tartrazine were almost90%for50mg·L-1of tartrazine.The results of column experiment indicated that the concentration of tartrazine could bereduced from55mg·L-1to20mg·L-1by SSAG. The pseudo second order kinetic model andLangmuir isotherm model were described well the tartrazine adsorption onto SS and SSAG.The tartrazine adsorption onto SSAG was also agreement with Freundlich isotherm model.The removal mechanism of tartrazine onto SS and SSAG were mainly physical reaction, theion exchange reaction. And the carboxyl group of benzene ring was possibly participated inthe reaction.（3） Decolorated efficiency of soy sauce were both high onto TASS and TSAG. Thechroma of soy sauce could be reduced from670to50by TASS and TSAG. Thedecoloration of soy sauce was occurred through complexation reaction between hydroxylgroups of adsorbent and the color group of soy sauce.The research provides valuable results on the removal of three kinds of contaminants inwastewater by sewage sludge and tannin-activated sewage sludge. It opens a new dimensionto sewage sludge resource.